Aerator with variable proportioning

ABSTRACT

The disclosure relates to water aerators of the type which are affixed to the discharge end of a water faucet in order to provide a soft, bubble-laden aerated stream. Jet-forming means or diaphragms are provided at the inlet end of the aerator to produce a plurality of high velocity jet streamlets which pass through a mixing space into which air enters through an air passageway. The jet streamlets and entrained air are then directed upon one or more of mixing screens with the result that the air becomes intimately admixed with the water so as to produce a highly aerated stream. A separate element is provided upstream of the jet forming diaphragm, and this element may be selectively inserted with either side facing upstream, or may be entirely removed. Dependent upon which of these several methods of assembly is employed, there results a substantially different proportioning between the velocity of the jet streamlets and the screen resistance so as to affect appreciably the degree of aeration of the stream, the amount of water flow, the amount of back pressure, and the effect of use of the aerator upon gas heater ignition which has been found to be adversely affected by the use of some types of water aerators.

United States Patent [72] inventor Elie P. Aghnides 795 Fifth Ave., New York, N.Y. 10021 [21] Appl. No. 702,358 [22] Filed Feb. 1, 1968 [45] Patented Jan. 12, 1971 Con nuation-in-part of application Ser. No. 616,286, Feb. 15, 1967, now Patent No. 3,417,924.

' [54] AERATOR WITH VARIABLE PROPORTIONING 18 Claims, 1 Drawing Fig.

[52] US. Cl 239/4285 [51] Int. Cl E03c 1/08 [50] Field ot'Seareh 239/4285 [56] References Cited UNITED STATES PATENTS 1,110,453 9/1914 Monosmith 239/4285 2,210,846 8/1940 Aghnides 239/4285 2,510,395 6/1950 Goodrie 239/4285 2,603,469 7/1952 Bedford et a1. 239/4285 2,811,340 10/1957 Aghnides 239/4285 2,950,063 8/1960 Ripley 239/4285 2,998,929 9/1961 Aghnides 239/4285 3,417,924 12/1968 Aghnides 239/4285 Primary Examinerl..loyd L. King Attorney-Hall, Pollock and Vande Sande ABSTRACT: The disclosure relates to water aerators of the type which are affixed to the discharge end of a water faucet in order to provide a soft, bubble-laden aerated stream. Jetforming means or diaphragms are provided at the inlet end of the aerator to produce a plurality of high velocity jet streamlets which pass through a mixing space into which air enters through an air passageway. The jet streamlets and entrained air are then directed upon one or more of mixing screens with the result that the air becomes intimately admixed with the water so as to produce a highly aerated stream. A separate element is provided upstream of the jet forming diaphragm, and this element may be selectively inserted with either side facing upstream, or may be entirely removed. Dependent upon which of these several methods of assembly is employed, there results a substantially different proportioning between the velocity of the jet streamlets and the screen resistance so as to affect appreciably the degree of aeration of the stream, the amount of water flow, the amount of back pressure, and the effect of use of the aerator upon gas heater ignition which has been found to be adversely affected by the use of some types of water aerators.

BACKGROUND OF THE INVENTION Millions of water aerators have been made in accordance with the disclosures of my basic U.S. Pat. Nos. 2,210,846 and 2,316,832. In these aerators, a jet-forming means projects jets of high velocity water over wire mesh screens in the presence of air, the jet velocity and screen resistance being proportioned so as to cause the production of a soft, bubble-laden aerated stream. In aerators built in accordance with the first of the aforesaid patents, No. 2,210,846, inwhich the jet-forming means comprised a single diaphragm member, the issuing bubbly stream was harsh and uneven unless greater screen resistance was used which decreased aeration. This shortcoming was remedied by the devices disclosed in my U.S. Pat. Nos. 2,316,832 and 2,104,824 which provide a second diaphragm upstream the diaphragm which produces said jets. Practically all aerators now in use have such two diaphragms, or the single diaphragm of my later U.S. Pat. No. 2,998,929 which delivers highly swollen jets requiring even less screen resistance than do the jets from the two diaphragrns of my U.S. Pat. No. 2,316,832 in order to produce an even and soft, highly bubbleladen stream. 1

Aerators constructed in accordance with the aforesaid U.S. Pat. Nos. 2,210,846 and 2,316,832 have been in widespread use to produce such a highly aerated stream despite a significant decrease in water flow and a resulting high pressure which may tend to increase the leakage of water past the packings used in the faucet. Moreover, in recent years, it has been found that the high back pressure resulting from the use of aerators designed to produce a highly aerated'stream will often prevent the automatic ignition of gas fired heaters. In order to overcome this, aerators are now being made and sold having a greater number of orifices in the diaphragrns or with bigger orifices, so that whereas the back pressure with the earlier types of aerators was often in the 'order'of 30 pounds per square inch, with the new type of aerators it is usually only about pounds per square inch.

The provision of more, and/or bigger orifices in .the diaphragm results in the delivery of more water with less jet velocity over a screen area which is no bigger than before. It

has been well established that in order to provide optimum.

aeration, it is necessary to have a predetermined relationship element in the water aerator to produce a high degree of aeration, and, on the other hand, significantly lower jet velocity and back pressure, with corresponding decrease in the degree of aeration so as to decrease the back pressure or to increase rate of flow, or to remove interference with gas heater ignition with another, different assembly of the aforesaid element in the aerator.

Thus, to minimize or even eliminate heater ignition interference and also leakage past the faucet packing, or restriction of water flow, the aerator is so built as to permit, when necessary, a reduction in resistance to water flow presented by the jet-forming means. This is accomplished by increasing the ef fective number, and/or effective cross-sectional area of the multiplicity of through passages in the jet forming means. in the specific embodiments disclosed herein, a partially imperforate disc or the like is used which selectively blocks or restricts some of said through passages of the jet-forming means so as to produce a high jet velocity, high back pressure, and a high degree of aeration and, alternatively, low jet velocity, low back pressure, and a lowered degree of aeration.

In the first instance, where there is a partial obturation or restriction of some of the orifices, proper design of the aerator ensures that there is still a normal rate of flow of water delivered; whereas, in the second instance, an increased rate of water flow is permitted through the jet-forming means. The aerator and the element included therein, may be so designed as to permit, in one position of the latter, a well-aerated flow comparable in volume and aeration to that of earlier aerators, and another position to decrease said flow and permit good aeration at low water pressures (or to save water at high water pressures), and upon removal of the element, to cause the lowering of the back pressure with a corresponding increase of the rate of water flow and impairment of aeration.

Although it is known in the art to provide an insert in an aerator which has the function of partially obturating or restricting the water passages through a jet-forming means, and/ordirect obturation of some of the orifices of the diaphragm delivering the jet streamlets, such elements have generally been constructed so as to accomplish this particularly with respect to a peripheral row of orifices in the jetforming means. When this is done, it is found that the aerated stream issuing from the aerator is very much reduced in crosssectional area and is an unsteady, harshly defined stream, very much unlike the aerated streams of water that will issue from the aerator when the outer peripheral row is not blocked or between the jet velocity of the strearnlet and the screen resistance. However, such a modification of a water aerator as to provide more or bigger holes for the jet-forming means produces a substantial departure from optimum conditions so that such aerators neither provide the benefits :of a fully t aerated drinking water nor the high degree of effervescence of the original bubbly stream which was pleasanter to the touch and washed faster. However, manufacturers of water aerators have found it impractical to market one type of aerator with a high degree of aeration and another which produces only a very low back pressure; consequently, those who do not emloy gas-fired heaters on their premisesand therefore do not have a heater ignition problem, like those who are not concerned with increased rate of flow or with decreased back pressure, are deprived of the benefits of having properly aerated water.

In accordance with the present invention, many of the foregoing problems are overcome by providing an element which is assembled within the aerator, preferably above the jet-forming means. Such element may be reversible in position and also removable and is capable,'when in position, of selectively blocking, wholly or partially, some of the through passages of the jet-forming means, or may be capable, in some embodiments, of accelerating the velocity of some or all of the streams issuing from the jet-forming means.

The aerator is so designed that it provides substantially the desired proportioning between jet stream velocity and screen resistance according to one assembly of the aforementioned restricted, or when blockage or restriction is applied to through passages provided upstream the orifices delivering the jet streamlets to the mixing chamber, in which event, the

' aerated issuing stream is roundedand soft, as well as being uniform in dimensions and appearance with passage of time. Accordingly, the concept and means of the present invention for providing an aerator with adjustable proportioning is quite different from what is disclosed and claimed in my prior U.S. Pat. Nos. 2,774,584 and 2,811,340. The prior art adjustable aerators designed to effect high degrees of aeration, with or without restriction of flow, were not properly proportioned for neither rate of flow, and the issuing bubbly stream was uneven and harsh in both cases. In contrast, the objective of the present invention is to provide the proportioning required for a fully bubble laden soft stream when the flow through the jetforrning means is restricted, and to produce, at a less desirable proportioning, a less aerated, but nevertheless even and soft, stream to lower the back pressure when the restriction is removed or lessened.

Further, while the adjustable prior art areas were solely intended to increase back pressure when the water pressure was low, to permit good aeration, the aerators of the present invention are intended in some constructions to decrease the back pressure, irrespective of the degree of water pressure, if the existence of gas heaters on the linerequires the housewife to do so. In other constructions, it permits a low rate of flow for the saving of water as is particularly desirable at times in industrial and public buildings. Finally, it makes possible the attainment of good aeration at low water pressure. Moreover, while the flow'restricting means of adjustable prior art aerators are either applied to aerators embodying a single diaphragm so as to obturate directly some of the orifices which project streamletsupon the mixing screens resulting in the delivery of a harsh stream, or closed the peripheral holes of the downstream diaphragm as aforesaid with the result that the issuing stream was thin and splashy, in the present invention, by contrast, the restriction or obturation is effected upstream in such a way that in some cases all of the orifices which project jets of water over the screens may be left open so that the resulting stream of aerated water is even and soft.

In addition, whereas the flow restricting means of adjustable aerators of the prior art requires manual controls from the outside, were costly and unattractive, the element of the present invention is accessible only upon removal of the aerator from the faucet, is simple in construction, and therefore costs very little to make.

Consequently, the objectives sought by the prior art adjustable aerators, namely the provision of a fully bubble-laden, even, and soft stream at high as well as low water pressures, could not be obtained. The housewife would always select the position giving a poorly aerated but less splashy high rate of flow in lieu of a highly aerated butharsh and splashy stream. With the aerator of the present invention, on the other hand, the element, with its preset proportions will always give an antisplash and even stream, with a predetermined degree of aeration for each of its positions. As a result, in cities without gas-fire heaters, the aerators of this invention nevertheless prove attractive since they provide full aeration; in locations where water heaters are used, but on faucets not used in proximity to such water heaters, the element can still be placed in such a position as to provide the best degree of aeration. In all instances, however, the element may either be turned upside downwithin the aerator or removed so as to permit control of the back pressure and rate of water flow.

Another attribute of this invention is that the aforesaid element has substantially utility as a filter elementQThus, such element is ordinarily provided with a considerable number of apertures whose maximum dimension is such to enable it to entrain sediment and other particles which would otherwise clog in either the normal jet-forming means or the downstream mixing screens.

Further, whereas in prior adjustable aerators, the holes of the single perforate disc in the diaphragm are closed or restricted, either by a closely contacting upstream disc or by the sealing periphery of a second diaphragm placed upstream said perforate disc, in the present invention, the element causing the restriction of flow is located over the upstream side of the through passages of the jet-forming means disclosed in one or the other of my aforesaid three patents. The flow restricting element may, or may not embody said filter element- Also, it may, or may not, embody said sealing periphery, the embodiment of which in said element makes it'possible to dispense with the use of'a washer.

BRIEF DESCRIPTION OF THE DRAWINGS In describing the invention in detail, reference will be made to the accompanying drawing in which: FIG. 1 is a cross-sectional view of an aerator according to one embodiment of the invention;

FIG. 1A and 1B illustrate alternative of FIG. I;

FIG. IS A cross-sectional view of an ment of the invention; 7

FIGS. 2A and 2B illustrate plan views of the aerator of FIG. 2 according to two alternative embodiments;

FIG. 3 is a cross-sectional view of a further embodiment of the invention;

FIG. 4 is a cross-sectional view of an alternative form of jetforming means and insert adapted for use in an aerator of the tvve shown in FIG. 3;

forms of the invention alternative embodi- FIGS. 4A and 4B illustrate alternative embodiments of an insert adaptable for use with the embodiment of FIG. 4A; and

FIG. 5 is a cross-sectional view of still another embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The aerator of FIG. 1 comprises an outer cylindrical casing 10 having an interior upstream ledge. 11 which supports an annular inner casing member 12.'The member 12 defines an annular air passageway 13 extending from-the downstream or discharge end of the aerator to the mixing. space 14, the air entering into the mixing space through thecircumferential openings 15 in member 12. Member 12 has an; intumed ledge 16 at the bottom which supports a plurality of mixing screens 17 in stacked relation. Near its upstream end, member 12 is provided with an annular inttirned ledge 18 which supports two spaced diaphragm members 19 and 20, each havinga plurality of holes 21 and 22, respectively.

Positioned at the top of the uppermost diaphragm member 20 is a flow control member 23 which is provided with a plurality of through apertures 24 and an annular supporting ring 25 which may serve as a sealing washer and thereby eliminate the need for the washer ordinarily used for this purpose. When this element 23 is in the position shown, the plurality of annular rings, the upper diaphragm 20, and this comes about because the. bottom surface 27 of each of the annular rings 26 is essentially coplanar with the bottom surface 28 of ring 25, thereby permitting each bottom surface of a ring 26 to lie against the upper surface of diaphragm member 20. Incidentally, it should be noted that the outermost peripheral ring of holes in the upper diaphragm member 20 are left unblocked, and only the inner rows of apertures are blocked. As mentionedpreviously, this ensures that the aerated stream issuing from the aerator will be a full, rounded stream. i I

If the element 23 of FIG. 1 is inverted, the annular rings 26, will then obviously no longer block any of the through passages in the upper diaphragm member 20; instead, water will then pass through the orifices 24 and through all of the through passages 22 in the upper diaphragm member 20. Thus there is then very much less restriction in the flow of water through the upper diaphragm member 20 although, quite 'obviously, ,more restriction of water flow exists than if the member 23 is not even present within the aerator.

With the element 23 in the position shown in FIG. I, the proportioning of the jet velocity of streamlets issuing from the diaphragm members 20 and 21 is so related to the screen resistance ofi'ered by the mixing screens 17 as to produce substantially optimum water aeration. When the element 23 is reversed in position, there is a significant reduction in jet velocity and in back pressure, butstill providing good aeration at low water pressures, and/or a saving of water at high water pressures. Finally, the element 23 may be entirely removed from the aerator assembly, thereby completely removing the restriction of flow through the jet-forming elements 19 and 20 with a resultant lowering of back pressure, a corresponding increase of rate of flow, together with some impairment of the degree of water aeration.

The alternative embodiment of FIG. 1A illustrates jet-form It has been mentioned previously that blocking the exterior or peripheral rows of holes of the jet-forming means results in a nonrounded, and splashy stream. These drawbacks are considerably lessened, when, in accordance with the embodiment of FIG. IA, the lower jet-forming element 19a is provided with 26v effectively block many of the through passages in ble downstream space even through the outer rows of apertures do not receive jets of water impinging thereon because of the blockage effect provided by the element 230 when in the position shown in FIG. 1A. When element 230 is removed, the diaphragm members 190 and 20a will operate as disclosed in my Pat. No. 3,316,832. The back pressure is thus very substantially reduced and the rate of water flow increased.

In the embodiment of FIG. 1B, the flow control element 23b has an annular sealing rim 30 which in the position shown in FIG. 18, spaces the bottom surface of the element 23b from the upper surface of the perforated jet-forming element 31. (In FIG. 1B, only the upper of the two jet-forming elements is shown, but it will be understood that two such elements can be provided as shown for example in FIG. I.) It'will also be apparent from FIG. 18 that if the element 23b is reversed in position, the upwardly extending portion 32 which is coplanar with the upper edge of the annularfsealing ring 30 will then rest directly upon the upper surface of element 31 so as to close ofi the inner rows of holes 33, leaving, however, the outer rows of holes open so that a fully rounded stream of aerated stream of water will in any event be produced.

With the element 23b in the position shown in FIG. 1B moderate aeration and low back pressures result. When the element 23b is reversed in position a fully aerated stream is produced, but with higher back pressure and lower water flow. When the element 236 is entirely removed, impaired aeration results, but the back pressure is then at its lowest and a full flow of water results.

Referring now to FIG. 2 there is shown the single diaphragm element of my prior US. Pat. No. 2,998,929. Assuming that the flow control element 34 is not in place, water will enter each of the holes 35, 36, and 37 from either side of the respective bridges 39, 40 and 41, thereby providing a tortuous path for each stream of water which tends to produce a swollen jet. The flow control element 34 is provided with a plurality of annular depending portions 42 and 43 (shown also in the plan view of FIG. 2) which enter into the space between the successivebridgessoastoobturate,atleastinpart,thepassages which provide water to the holes -37. The cross-sectional viewofl-IG. 2showsalsooneot'theradialwebs44whichinterconnecm the successive depending annular portions 42 and 43toeachotheraswellastothehubportion 45 andtheannular ring 46 which may act as a sealing-washer, Member 34 fits over the upstanding portion 59:: of one-piece diaphragm 50.

Positioned atop member 34 is a filter screen 47 which blocks particles that would otherwise obstruct the passages in the diqihragm or mixing screens. As an alternative, the screen 47 may be removed and then instead the portions which lie between the ring-shaped portions 43 and 42 (see .FIG. 28) may be divided by a plurality of closely spaced annular slots 420 whose radial spming is such that they will trap sediment andotherparticlesandthusactasascreen.

As with the previously described embodiments, the element 34 may be either placed in the position shown or may be inverted. When inverted, the annular portions 42 and 43 no longer protrude into the space between the successive bridge portions 39, 44, and 41. Moreover, it will be noted that the spacing4lontheouterannularring46islesthanthatofcorresponding portion 49 with the result that when the element 34 is reversed in position, there will be some clearance between the top ofeach ofthe annular bridges 39, and 41 and the adjacent surface of the element 34 so that there will be less of a restriction of water flow into the holes 35-37. Again, the element 34 may be entirely removed so as to provide even less obturation of the passages through the jet-forming means.

FIG. 3 is a partial view of an all-plstic, one-piece aerator as disclosed in my US. Pat. No. 3,370,964. In FIG. 3, the flow control element 52 has depending annular portions 53 and 54. The portion 53 fits in the annular groove 55 so as to block one entry to the passage 56, and the depending annular portion54 together with the remainder of the portion 53 completely block off the holes 57. Consequently, jets of water will emerge from holes 58 and from holes 56, but with the latter partially obstructed. Obviously, when the element 52 is reversed in position, none of the passages 56, 57, or 58 is wholly blocked so that there is substantially less obstruction of the single piece diaphragm with a resultant decrease in back pressure. However, even with the element 52 in reverse position, there is some obturation of flow because of the fact that water can only pass through the plurality of small passages 59 provided in element 52. Consequently, when the element 52 is entirely removed, there is still less flow restriction with a corresponding decrease in back pressure and increase of water flow.

In the embodiment of FIG. 4 the flow control element 60 has a central stem 61 which is adapted to be threaded at its lower end into diaphragm 62. The element 60 has a plurality of apertures 62 therein which permits some flow of water into the two inner rows of passages 63 and 64. The outer row of passages are also only partially obturated by element 60. With element 60 in place a high degree of aeration is provided with a corresponding fairly high back pressure. When element 60 is removed, the back pressure is considerably lowered.

FIG. 4A illustrates an element 70 which may be used in connection with the diaphragm 62 of FIG. 4 in place of the flow control element 60. When placed on top of the diaphragm 62,

with the collar portion 68 facing upwardly as in FIG. 4A,

water can flow only restrictedly from each of the holes 63-65. However, when the element is placed in the inverted position, the collar 68 fits quite snugly into the inner circular space defined by bridge 69 so as to partially obturate the innermost row of holes 64. Element 70 is centered relative to diaphragm 62 by means of three or more outwardly extending, circumferentially spaced legs 71.

Element 70 may not only be used in place of element 60 of FIG. 4 but may also be placed on top of element 60 in order to block pasages 60. This may be done when improved aeration is desired under very low water pressure conditions or when it is desired to reduce water consumption.

FIG. 48 illustrates still another flow control element 72 which may be used in place of element 60 of FIG. 4. The inner hub fits within the recess'defined by annular bridge 69 and thereby partially obturates the innennost row of pasages 64. Inner wall 74 is dimensioned to snugly fit over the annular bridge 74a of FIG. 4, thereby completely blocking holes 63 in diaphragm 62 to provide the highest velocity of the jet streamlets, the least rate of water flow, andthe greatest back pressure.

FIG. 5 illustrates an aerator unit which is intended to be inserted into a casing such as a casing 10 of FIG. 1. The sleeve 75 which supports the mixing screen 76 is connected to ring 77 by ribs 78 and 79, which are integral with ring 77 and ribs 88, the latter being connected to the outer ring 80. Member 81 is connected to ring 77 by webs 82. Indentations 83 are provided in the inturned ledge 84 in order to permit the lower portion of a two-piece die which forms the unit to enter from the bottom and, by means of longitudinal ribs on such die portion, form such indentations 83 and thereby prevent the downward continuance of the ribs 78 and 79 which are formed by the upper die member. This makes possible the molding of the entire unit from a single piece except for screen 76 and the upper reversible perforate diaphragm member 85.

In the position shown for the diaphragm member 85, the inner row of apertures 86 are entirely blocked, but when the element is reversed in position, these apertures as well as the outer row of apertures 87 are open to thereby permit a lowering of the back pressure.

Having described several embodiments of my invention, I desire it to be understood that various modifications and alterations may be made to the specific fonns shown without departing from the spirit or scope of this invention.

I claim:

1. A water aerator comprising in combination:

an outer casing adapted to be secured to the discharge end of a water faucet;

an upstream jet-forming .means supported by said casing and defining a multiplicity of apertures therethrough, downstream mixing screens;

means defining an air inlet passageway for conducting air to a mixing space between said jet-forming means and said mixing screens;

a fiow control means positioned upstream of said jet-forming means for obturating at least some of the apertures therein to increase the velocity of the jet streamlets impinging upon said mixing screens; and

said fiow control means being reversible in'position and in one of its positions obturating the apertures in said jetforrning means to a greater degree than in the other of said positions; said flow control element in one position providing a high degree of aeration together with high back pressure and low rate of water flow, in the other position providing effective aeration and less back pressure, and when removed providing lowest back pressure and greatest rate of water flow.

2. A water aerator comprising in combination;

an outer casing adapted to be secured to the discharge end of a water faucet;

an upstream jet-forming means supported by said casing and defining a multiplicity of apertures therethrough, downstream mixing screens;

means defining an air inlet passageway for conducting air to a mixing space between said jet-forming means and said mixing screens;

a flow control means positioned upstream of said jet-fonning means for obturating at least some of the apertures therein to increase the velocity of the jet streamlets impinging upon said mixing screens;

said fiow control means comprising a circular disc supported by an encircling annular member having top and bottom supporting surfaces;

said disc having on one side only at least one depending annular portion adapted to lie against the upper surface of said jet-forming means when said flow control means rests with one of its said supporting surfaces on said jetforrning means so as to block at least some of the apertures in said jet-forming means; and

said flow control means in the reversed position leaving the apertures of said jet-forming means substantially unobstructed.

3. The aerator of claim 2 which further includes a filter screen on the upstream side of said fiow control means.

4. The aerator of claim 2 inwhich said flow control means includes a plurality of said spaced annular depending rings which are joined by radially extending webs, the annular said successive rings being subdivided by a spaces between plurality of annular through slots to form thereby a filter means.

5. A water aerator comprising in combination: an outer casing adapted to be secured to the discharge end of a water faucet; an upstream jet-forming means supported by said casing and defining a multiplicity of apertures therethrough, downstream mixing screens; means defining an air inlet passageway for conducting air to a mixing space between said jet-forming means and said mixing screens; a

a flow control means positioned upstream of said jet-forming means for obturating at leastsome of the apertures therein to increase the velocity of the jet streamlets impinging upon said mixing screens;

said jet-forming means comprising two superposed apertured discs;

the lower of said apertured discs comprising at least in part a concave portion to cause the jets issuing from the apertures in said concave portion to .be divergent; and

said flow control means being reversible in position and in one position thereof obturating the peripheral row of apertures in the upper of said jet-forming discs.

6. Awater aerator comprising in combination:

an outer casing adapted tobe secured to the discharge end of a water faucet;

an upstream jet-forming means supported by said casing and defining a multiplicity .of apertures therethrough, downstream mixing screens; i

vmeans defining an air inlet passageway for condiicti'rigai'r to a mixing space between said jet-forrning in and said mixing screens;

fiow control means positioned upstrearnof forrning means for obturating at least som'e of tliiipertures therein to, increase the velocity of the jet streamlets impinging upon said mixing screens;

said jet-forming means comprising twtVsu'perposed apertured discs; I I

said jet-forming means comprising a unitary element defining a plurality of tortuous parts therethrough;

the upstream side of said unitary element defining therein apertures in the sides of said ridges communicating with said partially blind apertures; and

said fiow control element on one surface thereof defining at least one depending annular ridge adapted to fitinto the annular space between successive of said ridges and thereby block at least some of said apertures in'the sides of said ridges.

7. A water aerator comprising in combination:

an outer'casing adapted to be secured to the discharge end of a water faucet; v i

an upstream jet-forming means supported by said casing and defining a multiplicity of apertures therethrougli, downstream mixing screens; g I

means defining an air inlet passageway for conducting air to a mixing space between said jetrforming means and said mixing screens; i v. A

a fiow control means positioned upstream of said jet-forming means for obturating at least some of the apertures therein to increase the velocity of the jet streamlets impinging upon said mixing screens;

said jet-forming means comprising two superposed apertured discs; t

said jet-forming means comprising a unitary element defining a plurality of tortuous parts therethrough; I

the upstream side ofsaid unitary element defining therein a plurality of spaced annular upstanding ridges overlying annular rows of partially blind apertures in said element and also defining apertures in the sides of said ridges communicating with said partially blind apertures; and

said'flow control element comprising a substantially flat disc adapted to overlie the upper surface of said unitary ele- .ment and block some of the passages therein.

8. The aerator of claim 7, in which said flow control means comprises a central stern normal to the plane of said disc and adapted for threaded engagement into said unitary element.

; 9. The aerator of claim8 in which said flat disc is provided with a plurality of apertures.

10. The aerator of claim 9 which further includes an auxiliary disc adapted to overlie said fiat disc to block at least some of the. apertures therein. t

1 l. A water aerator comprising in combination:

' an outer casing adapted to be secured to the discharge end I of a water faucet; Y

an upstream jet-forming-means supported .by said casing "and defining a multiplicity of apertures therethrough,

downstream mixing screens;

means defining an airinlet passageway for conducting air to a mixing space between said jet-forming means and said mixing screens;

a fiow control means positioned upstream of said jet-forming means for obturating at least some of the apertures therein to increase the velocity of the jet streamlets impingingupon said mixing screens;

said jet-forming means .comprising an imperforate circular member;

an annular shell connected to said circular member .by a plurality of webs as to provide a restricted annular space therebetween;

said flow control means including an upstream element having a plurality of apertures therein;

and means for reversibly supporting said flow control means immediately upstream of said circular member; and

said supporting mean: in one position of said flow control means blocking some of the apertures therein by said circular member but in the other position leaving said apertures unobstructed.

12. A water aerator of the type comprising an annular casing adapted for securing to the discharge end of a water faucet, a jet-forming means having a plurality of orifices for producing a plurality of streamlets, downstream mixing means, and means defining an air inlet passage from the atmosphere to a mixing space between the jet-forming means of the mixing means, the improvement which comprises, a means adapted for bistate assembly in said aerator and comprising an element which in accordance with one state of assembly of the component parts of said aerator is positioned above and at least partially obturates some of the through passages of said jet-forming means, and in accordance with the second state of assembly permits unobstructed flow through the orifices of said jet-forming means, said jet-forming means with said element in accordance with said one assembly providing a velocity of the jet streamlets issuing from said jet-forming means which is so proportioned relative. to the resistance presented by said mixing means as to provide a high degree of water aeration and high back water pressure, said jet-forming means with said element in accordance with said second assembly providing a substantially lower velocity of said jet streamlets which is so proportioned relative to said mixing means resistance as to provide a substantially lower water pressure and a lower degree of water aeration.

13. The water aerator of claim 12 in which said element comprises an imperforate disc adapted to be superimposed on said jet-forming means and having an imperforate central portion and a plurality of radially extending legs to center said element relative to said jet-forming means.

14. The water aerator of claim 12 in which said jet-forming means comprises an upper surface having a plurality of annular, spaced, upstanding protuberances. and said element com prises a ring-shaped member fitting with a sealing engagement in the groove between a successive pair of said annular protuberances.

15. The water aerator of claim 12 in which said element comprises a disc and an axially extending integral shaft adapted for frictional engagement with an aperture in said jetforming means.

16. The water aerator of claim 1 in which said element comprises a central imperforate portion adapted to closely overlay and partially obturate the through passages of said jet-forming means when said element is placed with a first side thereof facing upstream, said element being provided with spacer means for spacing said central imperforate portion from the orifices in said jet-forming means when said element is placed upon said jet-forming means with the opposite side thereof facing upstream.

17. The water aerator of claim 16 in which said element further includes an annular gasket portion and integral means connecting said gasket portion with said central imperforate portion.

18. The aerator of claim 15 in which said jet-forming means comprises at least two spaced perforate discs, one of said discs having an axially extending protuberance adapted to block some of the apertures in the other of said discs when said one disc has a first side thereof facing upstream, said protuberance facing in the opposite direction axially when said one disc has its first side thereof facing downstream so as to leave said apertures in the other disc unobstructed. 

1. A water aerator comprising in combination: an outer casing adapted to be secured to the discharge end of a water faucet; an upstream jet-forming means supported by said casing and defining a multiplicity of apertures therethrough, downstream mixing screens; means defining an air inlet passageway for conducting air to a mixing space between said jet-forming means and said mixing screens; a flow control means positioned upstream of said jet-forming means for obturating at least some of the apertures therein to increase the velocity of the jet streamlets impinging upon said mixing screens; and said flow control means being reversible in position and in one of its positions obturating the apertures in said jet-forming means to a greater degree than in the other of said positions; said flow control element in one position providing a high degree of aeration together with high back pressure and low rate of water flow, in the other position providing effective aeration and less back pressure, and when removed providing lowest back pressure and greatest rate of water flow.
 2. A water aerator comprising in combination; an outer casing adapted to be secured to the discharge end of a water faucet; an upstream jet-forming means supported by said casing and defining a multiplicity of apertures therethrough, downstream mixing screens; means defining an air inlet passageway for conducting air to a mixing space between said jet-forming means and said mixing screens; a flow control means positioned upstream of said jet-forming means for obturating at least some of the apertures therein to increase the velocity of the jet streamlets impinging upon said mixing screens; said flow control means comprising a circular disc supported by an encircling annular member having top and bottom supporting surfaces; said disc having on one side only at least one depending annular portion adapted to lie against the upper surface of said jet-forming means when said flow control means rests with one of its said supporting surfaces on said jet-forming means so as to block at least some of the apertures in said jet-forming means; and said flow control means in the reversed position leaving the apertures of said jet-forming means substantially unobstructed.
 3. The aerator of claim 2 which further includes a filter screen on the upstream side of said flow control means.
 4. The aerator of claim 2 in which said flow control means includes a plurality of said spaced annular depending rings which are joined by radially extending webs, the annular spaces between said successive rings being subdivided by a plurality of annular through slots to form thereby a filter means.
 5. A water aerator comprising in combination: an outer casing adapted to be secured to the discharge end of a water faucet; an upstream jet-forming means supported by said casing and defining a multiplicity of apertures therethrough, downstream mixing screens; means defining an air inlet passageway for conducting air to a mixing space between said jet-forming means and said mixing screens; a flow control means positioned upstream of said jet-forming means for obturating at least some of the apertures therein to increase the velocity of the jet streamlets impinging upon said mixing screens; said jet-forming means comprising two superposed apertured discs; the lower of said apertured discs comprising at least in part a concave portion to cause the jets issuing from the apertures in said concave portion to be divergent; and said flow control means being reversible in position and in one position thereof obturating the peripheral row of apertures in the upper of said jet-forming discs.
 6. A water aerator comprising in combination: an outer casing adapted to be secured to the discharge end of a water faucet; an upstream jet-forming means supported by said casing and defining a multiplicity of apertures therethrough, downstream mixing screens; means defining an air inlet passageway for conducting air to a mixing space between said jet-forming means and said mixing screens; flow control means positioned upstream of said jet-forming means for obturating at least some of the apertures therein to increase the velocity of the jet streamlets impinging upon said mixing screens; said jet-forming means comprising two superposed apertured discs; said jet-forming means comprising a unitary element defining a plurality of tortuous parts therethrough; the upstream side of said unitary element defining therein apertures in the sides of said ridges communicating with said partially blind apertures; and said flow control element On one surface thereof defining at least one depending annular ridge adapted to fit into the annular space between successive of said ridges and thereby block at least some of said apertures in the sides of said ridges.
 7. A water aerator comprising in combination: an outer casing adapted to be secured to the discharge end of a water faucet; an upstream jet-forming means supported by said casing and defining a multiplicity of apertures therethrough, downstream mixing screens; means defining an air inlet passageway for conducting air to a mixing space between said jet-forming means and said mixing screens; a flow control means positioned upstream of said jet-forming means for obturating at least some of the apertures therein to increase the velocity of the jet streamlets impinging upon said mixing screens; said jet-forming means comprising two superposed apertured discs; said jet-forming means comprising a unitary element defining a plurality of tortuous parts therethrough; the upstream side of said unitary element defining therein a plurality of spaced annular upstanding ridges overlying annular rows of partially blind apertures in said element and also defining apertures in the sides of said ridges communicating with said partially blind apertures; and said flow control element comprising a substantially flat disc adapted to overlie the upper surface of said unitary element and block some of the passages therein.
 8. The aerator of claim 7, in which said flow control means comprises a central stem normal to the plane of said disc and adapted for threaded engagement into said unitary element.
 9. The aerator of claim 8 in which said flat disc is provided with a plurality of apertures.
 10. The aerator of claim 9 which further includes an auxiliary disc adapted to overlie said flat disc to block at least some of the apertures therein.
 11. A water aerator comprising in combination: an outer casing adapted to be secured to the discharge end of a water faucet; an upstream jet-forming means supported by said casing and defining a multiplicity of apertures therethrough, downstream mixing screens; means defining an air inlet passageway for conducting air to a mixing space between said jet-forming means and said mixing screens; a flow control means positioned upstream of said jet-forming means for obturating at least some of the apertures therein to increase the velocity of the jet streamlets impinging upon said mixing screens; said jet-forming means comprising an imperforate circular member; an annular shell connected to said circular member by a plurality of webs as to provide a restricted annular space therebetween; said flow control means including an upstream element having a plurality of apertures therein; and means for reversibly supporting said flow control means immediately upstream of said circular member; and said supporting means in one position of said flow control means blocking some of the apertures therein by said circular member but in the other position leaving said apertures unobstructed.
 12. A water aerator of the type comprising an annular casing adapted for securing to the discharge end of a water faucet, a jet-forming means having a plurality of orifices for producing a plurality of streamlets, downstream mixing means, and means defining an air inlet passage from the atmosphere to a mixing space between the jet-forming means of the mixing means, the improvement which comprises, a means adapted for bistate assembly in said aerator and comprising an element which in accordance with one state of assembly of the component parts of said aerator is positioned above and at least partially obturates some of the through passages of said jet-forming means, and in accordance with the second state of assembly permits unobstructed flow through the orifices of said jet-forming means, said jet-forming means with said element in accordance with said one assembly pRoviding a velocity of the jet streamlets issuing from said jet-forming means which is so proportioned relative to the resistance presented by said mixing means as to provide a high degree of water aeration and high back water pressure, said jet-forming means with said element in accordance with said second assembly providing a substantially lower velocity of said jet streamlets which is so proportioned relative to said mixing means resistance as to provide a substantially lower water pressure and a lower degree of water aeration.
 13. The water aerator of claim 12 in which said element comprises an imperforate disc adapted to be superimposed on said jet-forming means and having an imperforate central portion and a plurality of radially extending legs to center said element relative to said jet-forming means.
 14. The water aerator of claim 12 in which said jet-forming means comprises an upper surface having a plurality of annular, spaced, upstanding protuberances, and said element comprises a ring-shaped member fitting with a sealing engagement in the groove between a successive pair of said annular protuberances.
 15. The water aerator of claim 12 in which said element comprises a disc and an axially extending integral shaft adapted for frictional engagement with an aperture in said jet-forming means.
 16. The water aerator of claim 1 in which said element comprises a central imperforate portion adapted to closely overlay and partially obturate the through passages of said jet-forming means when said element is placed with a first side thereof facing upstream, said element being provided with spacer means for spacing said central imperforate portion from the orifices in said jet-forming means when said element is placed upon said jet-forming means with the opposite side thereof facing upstream.
 17. The water aerator of claim 16 in which said element further includes an annular gasket portion and integral means connecting said gasket portion with said central imperforate portion.
 18. The aerator of claim 15 in which said jet-forming means comprises at least two spaced perforate discs, one of said discs having an axially extending protuberance adapted to block some of the apertures in the other of said discs when said one disc has a first side thereof facing upstream, said protuberance facing in the opposite direction axially when said one disc has its first side thereof facing downstream so as to leave said apertures in the other disc unobstructed. 